s390/qeth: fix dangling IO buffers after halt/clear

The cio layer's intparm logic does not align itself well with how qeth
manages cmd IOs. When an active IO gets terminated via halt/clear, the
corresponding IRQ's intparm does not reflect the cmd buffer but rather
the intparm that was passed to ccw_device_halt() / ccw_device_clear().
This behaviour was recently clarified in
commit b91d9e67e50b ("s390/cio: fix intparm documentation").

As a result, qeth_irq() currently doesn't cancel a cmd that was
terminated via halt/clear. This primarily causes us to leak
card->read_cmd after the qeth device is removed, since our IO path still
holds a refcount for this cmd.

For qeth this means that we need to keep track of which IO is pending on
a device ('active_cmd'), and use this as the intparm when calling
halt/clear. Otherwise qeth_irq() can't match the subsequent IRQ to its
cmd buffer.
Since we now keep track of the _expected_ intparm, we can also detect
any mismatch; this would constitute a bug somewhere in the lower layers.
In this case cancel the active cmd - we effectively "lost" the IRQ and
should not expect any further notification for this IO.

Fixes: 405548959cc7 ("s390/qeth: add support for dynamically allocated cmds")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 14 deletions

diff --git a/drivers/s390/net/qeth_core_mpc.h b/drivers/s390/net/qeth_core_mpc.h
index 53fcf6641154..88f4dc140751 100644
--- a/drivers/s390/net/qeth_core_mpc.h
+++ b/drivers/s390/net/qeth_core_mpc.h
@@ -29,20 +29,6 @@ extern unsigned char IPA_PDU_HEADER[];
 #define QETH_TIMEOUT		(10 * HZ)
 #define QETH_IPA_TIMEOUT	(45 * HZ)
 
-#define QETH_CLEAR_CHANNEL_PARM	-10
-#define QETH_HALT_CHANNEL_PARM	-11
-
-static inline bool qeth_intparm_is_iob(unsigned long intparm)
-{
-	switch (intparm) {
-	case QETH_CLEAR_CHANNEL_PARM:
-	case QETH_HALT_CHANNEL_PARM:
-	case 0:
-		return false;
-	}
-	return true;
-}
-
 /*****************************************************************************/
 /* IP Assist related definitions                                             */
 /*****************************************************************************/